The article proposes the concept of constructing a comprehensive fiber-optic sensor (CFOS) for simultaneous measurement of relative humidity and air temperature, as well as the temperature of a solar cell. The sensor is represented by a double structure, consisting of a two-stage Fabry-Perot interferometer for measuring relative humidity and air temperature and a two-component wave addressable fiber Bragg structure for measuring the temperature of a solar cell. The sensor is inserted orthogonally to the plane of the solar photovoltaic panel into the technological hole formed in it so that the distance between the addressable fiber Bragg structure(s) and the Fabry-Perot interferometer module allows simultaneous measurement of relative humidity and air temperature, as well as the temperature of the solar panel. A change in relative humidity affects only the refractive index of the outer interferometer, while a change in air temperature affects the refractive index of both interferometers. Changing the temperature of the solar cell only affects the central wavelength of the addressable fiber Bragg structure. By solving a system of equations using the specified parameters, relative humidity and air temperature, as well as the temperature of the solar battery, can be controlled simultaneously. The structure and design of an integrated fiber-optic sensor and the results of the first experiments are presented, which confirmed the possibility of simultaneous measurement of the parameters under consideration that affect the efficiency of solar panels.
It is well known that the speed limitations inherent in conventional electronics can be overcome using photonic circuits, one of the main building blocks of which is a time differentiator. This device provides the time derivative of the complex envelope of an arbitrary input optical signal. Possible applications include optical pulse shaping, optical computing, information processing systems and ultra-high-speed coding, among other applications. The paper discusses the principles of constructing fractional order differentiators. Using the example of an asymmetric fiber Bragg grating with a π-phase shift operating in reflection, based on addressed fiber Bragg structure of Moiré type, the possibility of implementing a photonic fractional differentiator is shown. We present modeling of the characteristics of the spectral structures of a differentiator, which uses gratings of the same length, but with different modulation depths on both sides of the localization of the π-phase shift, using a new method of homogeneous layers.
Based on the analysis of methods and devices development for all-optical differentiation of signals and addressable fiber Bragg structures as sensitive elements of sensors, the possibility of combining the advantages of the latest versions of their implementation based on symmetric Moiré Bragg gratings has been found. For differentiators, which, as a rule, are considered as separate devices, the issues of their network multiplexing for a single module of photonic processing and computing of multiple signals, as well as the stability of differentiation characteristics with deviations in the temperature regimes of the laser and differentiator with a corresponding mismatch of their central wavelengths, are not touched upon. The advantages of microwave photonic processing of information used for addressable fiber Bragg structures will make it possible to solve the above problems of photonic differentiators when they are combined into a network. This conclusion is proved by the procedure presented in the report for the synthesis of addressable fiber Bragg structures of the Moiré type and the unity of their structure with the structure of photon differentiators.
The paper describes an approach to the construction of microwave photonic vector analyzers that allow assessing the transfer and linear characteristics of optoelectronic, electro-optical and optical elements. The approach is based on the use of two- and three-frequency probing radiation generated through modulation conversion in an electro-optical Mach-Zehnder modulator.
The requirements of the mass consumer and educational market impose great restrictions on the cost of hardware-software demonstrators with relatively low requirements for the characteristics of the quantum key distribution process. This means that these devices do not have to be advanced and, as such, can provide a dramatic reduction in size, weight, and power compared to other quantum key distribution systems. The article presents the stages of development and creation of an experimental prototype of a hardware-software demonstrator of a universal quantum key distribution system that implements existing methods based on amplitude and phase modulation, as well as the proposed method of tandem amplitude-phase modulation of an optical carrier. The evaluation of the technical, economic and operational characteristics of the hardware-software demonstrator was carried out; practical recommendations were formulated for its development, creation and operation, as well as for the choice of an import-substituting element base, which ensured its low cost and the possibility of wide use at various research and educational sites, including World Skills youth championships and Future Skills process. In addition, the proposed demonstrator, embedded in a desktop computer, can act as access devices that can be connected to a terminal combined with a quantum network node to replenish a secret key store, which can then be used to encrypt daily activities on conventional platforms such as the Internet.
Seven years ago, we proposed the concept of addressed fiber Bragg structures (AFBS), which simultaneously perform the functions of: a complexed sensitive element based on two FBGs (2λ-AFBS) with different Bragg frequencies or FBG with two π-phase shifts (2π-AFBS), the difference frequency of which is the AFBS address and the value of it is invariant to measured physical fields; a two-frequency laser radiation source, which can operate as in reflection, so as transmission mode respectively to structure above, a self-multiplexed set of sensors, if the difference frequency will be unique for each AFBS, enabling their address multiplexing. In this article, we consider the ontology of AFBS, including the parent structures with 2λ- or 2π-components, successor AFBS with three spectral components and various combinations of difference frequencies: symmetrical and asymmetric, performing the functions of the addressing and converting information signals to the low-frequency region at the same time, along with the functions of rejecting collisions caused by the relative movement of structures relative to each other during measurements. The subjects of interrogation of these structures and their calibration are discussed as well as prospects of AFBS further development based on common tasks born by ontology formalization and decisions of applicability tasks.
This work presents results of test series, performed for earlier on designed and successfully fabricated twisted silica fewmode microstructured optical fibers (MOF) with six GeO2-doped cores. While Part I introduces results of differential mode delay map measurements, Part II is focused on researches of spectral responses, measured for fiber Bragg gratings, recorded in these multi-core MOFs with core graded refractive index profiles and induced twisting 100 revolutions per meter. Specially setup for spectral response measurement for described complicated fiber optic element was developed, that provides selected alignment of matching singlemode optical fiber with particular single core of MOF via free space and reducing of reflection by precision 8 angle cleaving. Comparing analysis of measured spectral responses confirmed written FBGs in 2 of 6 cores, and demonstrated potentiality of fabricated complicated structure, containing multi-core MOF with FBG, for applications in multichannel fiber optic sensors with spatial division multiplexing technique.
The paper describes the problems of constructing optical branch analyzers. On the example of existing solutions (single-frequency scanning and microwave photonic methods), it is shown that these solutions have a number of limitations, which can be largely removed by a new approach to the construction of probing radiation. A description of the mathematical apparatus for restoring the contour characteristics is presented. A quantitative assessment of the dynamic and nonlinear characteristics of the probing radiation former are given.
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